A thermal solar panel of the type comprising at least one heat collecting element intended to receive solar rays is known from prior art. Such a solar panel is used, e.g., for coupling with a heat engine in order to transform solar heat energy into electrical or mechanical energy. In one variant, the solar heat energy may also be recovered in order to produce heat or cooling, e.g., for a heating or air-conditioning system.
Normally, the heat collection element is generally tubular in shape, and is arranged in a glass vacuum tube, coaxially with the glass tube. The solar panel includes, inter alia, reflective elements so as to focus the solar rays received on the heat collecting element.
The heat energy of the solar rays is then replaced by means of a coolant circulating in the core of the heat collecting element by means of heat transfer between the collector and the coolant.
The thermal performance of such a solar panel is generally limited by heat losses due to thermal radiation emitted by the heat collecting element. This thermal radiation is substantial, in particular, in case of high temperature and large surface area of the collector.
Thus, such a solar panel generally has low performance at high temperatures, e.g., at temperatures greater than 400° C.